What is the treatment for chickenpox?

Chickenpox Treatment

For healthy children, oral acyclovir (20 mg/kg four times daily for 5 days, maximum 800 mg per dose) should be initiated within 24 hours of rash onset if the patient is ≥13 years old, has chronic cutaneous or pulmonary disease, is receiving long-term salicylate therapy, or is on corticosteroid therapy. 1

Treatment Indications by Patient Population

Healthy Children and Adolescents

• Oral acyclovir is recommended for adolescents ≥13 years of age at a dose of 800 mg four times daily for 5 days 1
• Children with chronic cutaneous or pulmonary disorders require acyclovir therapy regardless of age 1
• Patients on long-term salicylate therapy should receive acyclovir to prevent Reye's syndrome risk 1
• Children receiving corticosteroid therapy (even short, intermittent, or aerosolized courses) warrant antiviral treatment 2
• For children <40 kg, the dose is 20 mg/kg per dose (maximum 800 mg) orally 4 times daily for 5 days 1

Immunocompromised Patients

• Immunocompromised patients require intravenous acyclovir 10 mg/kg every 8 hours for 7-10 days due to risk of severe, disseminated disease 1, 2
• This includes patients with hypogammaglobulinemia, those on high-dose immunosuppression (prednisolone ≥20 mg/day for ≥2 weeks), purine analogues, methotrexate, or biologic therapies 2
• Diagnosis relies on clinical features with or without PCR of vesicle fluid, as antibody titers are unreliable in patients with nephrotic-range proteinuria or those receiving IVIG 2

Pregnant Women

• Pregnant women without evidence of immunity exposed to chickenpox should receive varicella zoster immune globulin (VZIG) as soon as possible, up to 10 days after exposure 1
• Acyclovir is FDA Category B; while animal studies show no teratogenic effects, routine use is not recommended unless serious complications develop (e.g., pneumonia) 2, 3

Otherwise Healthy Children

• For immunocompetent children without risk factors, symptomatic treatment alone is typically adequate 4
• However, treatment with acyclovir within 24 hours of rash onset reduces lesion count (294 vs 347 lesions), accelerates healing, decreases fever duration, and limits constitutional symptoms to 3-4 days versus >4 days in 20% of untreated patients 5

Post-Exposure Prophylaxis

High-Risk Exposed Individuals

• VZIG should be administered as soon as possible, up to 10 days after exposure, for susceptible immunocompromised patients 1, 2
• If VZIG is unavailable, oral acyclovir 10 mg/kg four times daily for 7 days starting 7-10 days after exposure is recommended 1, 2
• VZIG is indicated for neonates born to mothers with varicella 5 days before to 2 days after delivery 1
• Premature infants <28 weeks gestation or <1,000 g should receive VZIG regardless of maternal immunity 1

Timing Considerations

• The 7-day acyclovir course should begin 7 days after exposure (not immediately), as this targets the incubation period 2
• Live varicella vaccination should be delayed 5 months after VZIG administration 1

Symptomatic Management

Pruritus Control

• Oral antihistamines are first-line for chickenpox-related itching: non-sedating options like fexofenadine 180 mg or loratadine 10 mg, or mildly sedating cetirizine 10 mg for nighttime relief 6
• Calamine lotion should NOT be used due to complete absence of supporting evidence 6
• Topical menthol preparations may provide additional relief if antihistamines are insufficient 6

Infection Control

• Patients should be isolated until all lesions have crusted over 1
• Healthcare workers without immunity exposed to VZV should be furloughed for days 10-21 after exposure 1

Alternative Antiviral Agents

FDA-Approved Options

• Valacyclovir is FDA-approved for chickenpox treatment in immunocompetent pediatric patients aged 2 to <18 years 7
• Valacyclovir dosing should be initiated within 24 hours of rash onset 7
• Famciclovir is approved for herpes zoster in adults and may be used as an alternative, though pediatric data are limited 2

Critical Pitfalls to Avoid

• Do not rely on antibody titers in patients with nephrotic-range proteinuria or those receiving IVIG, as results are unreliable 2, 1
• Do not administer live varicella vaccine to immunocompromised patients due to risk of disseminated infection 1
• Do not delay antiviral therapy beyond 24 hours of rash onset in patients requiring treatment, as efficacy diminishes significantly 1, 7, 5
• Do not use aspirin or salicylate-containing products in children with chickenpox due to Reye's syndrome risk 2
• Ensure adequate hydration in all patients receiving acyclovir to prevent nephrotoxicity 3